Generally, catalysts used for olefin polymerization can be classified into three categories: traditional Ziegler-Natta catalysts, metallocene catalysts, and non-metallocene catalysts. Regarding traditional Ziegler-Natta catalysts for propene polymerization, with the development of electron donor compounds in catalysts, polyolefin catalysts are also constantly undated. The development of catalysts has experienced the 1st generation of TiCl3AlCl3/AlEt2Cl system, the 2nd generation of TiCl3/AlEt2Cl system, the 3rd generation of TiCl4.ED.MgCl2/AlR3.ED system using magnesium chloride as carriers, monoester or aromatic diester as internal electron donor, and silane as external electron donor, and the newly developed catalyst system using diether compounds and diester compounds as internal electron donors. The activity of catalysts for catalyzing polymerization reaction and the isotacticity of the obtained polypropene has been greatly improved. In existing technologies, titanium catalysts used for propene polymerization mainly use magnesium, titanium, halogen, and electron donor as basic components, among which electron donor compounds are indispensible elements of catalyst components. Till now, various internal electron donor compounds have been disclosed, these compounds including, for example, monocarboxylic esters or polycarboxylic esters, acid anhydrides, ketones, monoethers or polyethers, alcohols, amines, and derivatives thereof, and so on, among which commonly used ones are aromatic dicarboxylic esters such as di-n-butyl phthalate (DNBP) or diisobutyl phthalate (DIBP), and so on. Reference can be made to U.S. Pat. No. 4,784,983. U.S. Pat. No. 4,971,937 and European patent EP0728769 disclose components of catalysts used for olefin polymerization, in which 1,3-diether compounds having two ether groups are used as electron donors, such compounds including, for example, 2-isopropyl-2-isopentyl-1,3-dimethoxy propane, 2,2-diisobutyl-1,3-dimethoxy propane, 9,9-di(methoxymethyl)fluorene, etc. Later, a class of special aliphatic dicarboxylic ester compounds, such as succinate, malonic ester, glutarate, and so on, are disclosed (see WO98/56830, WO98/56834, WO01/57099, WO01/63231, and WO00/55215). The use of such electron donor compounds can not only improve the activity of a catalyst, but also enable an obtained propene polymer to have a wider molecular weight distribution.
The most common non-metallocene catalysts for olefin polymerization are C═N polydentate ligand-containing transition metal complexes. For example, Brookhart et al first found that diimine late transition metal complexes had a relatively high catalytic activity when used for catalyzing olefin polymerization (Johnson L. K., Killian C. M., Brookhart M., J. Am. Chem. Soc., 1995, 117, 6414; Johnson L. K., Ecking S. M., Brookhart M., J. Am. Chem. Soc., 1996, 118, 267). Since then, the study of non-metallocene organic complexes has aroused great interest among researchers. In 1996, McConville et al reported a class of Ti and Zr metal complexes (as shown in Formula 1) chelating β-diamine, which were first examples of high-catalytic-activity N—N polydentate ligand-containing early transition metal complexes for catalyzing olefin polymerization (Scollard J. D., Mcconville D. H., Payne N. C., Vittal J. J, Macromolecules, 1996, 29, 5241; Scollard J. D., Mcconville D. H., J. Am. Chem. Soc., 1996, 118, 10008).

β-diamine complexes (as shown in Formula 2) are also a class of important N—N ligand-containing non-metallocene catalysts for olefin polymerization. Because of the specific structures of these complexes, the steric hindrance and electronic effect of the ligand can be easily regulated and controlled through the change of a substituent on arylamine. With the variation of metals and the surroundings of the ligand, the β-diamine ligand can bond in different ways to different metals to form different metal complexes. These ligand-containing compounds are advantageous in that they are easy to synthesize and easy to regulate and control in terms of structure, and are comparatively idea complexes for studying the relationship between the structure and the properties of a catalyst. Ligand-containing compounds with such structures have therefore attracted wide attention among researchers (Bourget-Merle L., Lappert M. F., Severn J. R., Chem. Rev., 2002, 102, 3031; Kim W. K., Fevola M. J., Liable-Sands L. M., Rheingold A. L., Theopoid K. H., Organometallics, 1998, 17, 4541; Jin X., Novak B. M., Macromolecules, 2000, 33, 6205).
Polyethylene Laboratory of Sinopec Beijing Research Institute of Chemical Industry disclosed, in Chinese patent CN 00107258.7, a class of bidentate ligand-containing metal complexes for use in the copolymerization reaction of ethylene, and later disclosed, respectively in Chinese patents CN 02129548.4 (2002), CN 200410086388.8 (2004), CN 200710176588.6 (2007), a similar transition metal complex catalyst for use in the copolymerization reaction of ethylene. Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences disclosed, in Chinese patents CN 201010554473.8 and CN 201010108695.7, a class of polydentate ligand-containing metal catalysts with similar structures, for use in the copolymerization reaction of ethylene to prepare ultra-low-branched high-molecular-weight polyethylene.
In the disclosure of the above patents, the catalysts used for olefin polymerization are relevant ligand-containing metal compounds. Up till now, seldom are there reports about the direct use of such ligand-containing metal compounds in the preparation of a catalyst for propene polymerization and reports about their use related to propene polymerization.